LI  B  R.AR.Y 

OF  THE 
UNIVERSITY 


LINOIS 

50.7 

L6b 
,.31-48 

gric  . 

QN  CIRCUUTING 


CHECK  FOR  UNBOUND 
r?RCUI.ATING  COPY 


.CIRCULATING 


CHECK  FOR  UNBOUND 
CIRCULATING  COPY 


UNIVERSITY  OF  ILLINOIS. 

Agricultural  Experiment  Station. 


URBANA,  APRIL,  189?. 


BULLETIN  NO.  40. 


CONTENTS — POTATOES,  EXPERIMENTS  OF  1892-3-4,  WITH  A  STATE- 
MENT OF  SOME  RESULTS  OBTAINED  AT  OTHER  STA- 
TIONS. 

FUNGUS    DISEASES    OF  THE  POTATO. 

AN    EXPERIMENT    TO    PREVENT    SCAB    AND    LEAF    BLIGHT 
OF    THE    POTATO. 


POTATOES,  EXPERIMENTS   OF  1892-2-4,  WITH    STATE- 
MENT OF  SOME  RESULTS  OBTAINED 
AT  OTHER  STATIONS. 

The  potato  is  grown,  probably,  over  a  wider  area  than  any  other 
one  of  our  food  crops,  and  forms  a  staple  only  less  in  value  for  Europe 
and  America  than  the  grain  and  hay  crops.  The  methods  of  growing 
are  the  results  of  at  least  two  hundred  and  fifty  years'  experience  at  the 
hands  of  intelligent  husbandmen,  and  it  would  scarcely  be  expected 
that  the  work  of  the  experiment  stations,  extending  over  so  few  years 
as  it  has,  would  make  much  change.  During  this  short  period,  how- 
ever, a  great  amount  of  work  has  been  done  at  the  thirty-six  different 
stations  in  the  United  States  which  have  worked  on  potatoes.  Many 
old  methods  have  been  proved  correct,  while  important  points  of 
progress  and  suggestions  for  change  have  been  made.  The  work  of 
the  experiment  stations  has  taken  the  following  general  lines  : 

Variety  tests. 

Change  of  seed  from  one  locality  to  another. 

Seed  from  best  and  poorest  hills. 

Seed  dug  early  as  compared  with  seed  dug  late  or  seed  of  second 
crop. 

119 


120  BULLETIN    NO.     40.  [April, 

Size  of  seed  pieces. 
Part  of  the  potato  to  be  used  for  seed. 
Preparation  of  the  soil. 
Time  of  planting. 
Depth  of  planting. 
Distance  apart  of  planting. 
Cultivation;  methods  and  frequency. 
Fertilizers. 

Quality  and  composition. 

Our  own  work  so  far  has  been  chiefly  on  teats  of  varieties,  of 
fertilizers  and  of  seed  from  different  sources. 

Variety    Tests. 

The  work  of  testing  the  varieties  of  potatoes  was  begun  in  1892. 
That  year  twenty  varieties  were  planted  May  6th,  and  twenty- eight 
more  on  the  28th  of  May.  Those  planted  at  the  earlier  date  made  a 
fair  average  growth  and  yield,  while  those  planted  at  the  later  date 
were  so  seriously  injured  by  the  drought  of  summer  that  no  account  was 
taken  of  them.  In  fact  most  varieties  planted  at  the  later  date  produced 
no  marketable  potatoes. 

On  the  loth  to  the  i2th  of  April,  1893,  potatoes  under  no  different 
names  were  planted.  Some  of  these  were  planted  in  duplicate  plats;  in 
most  of  these  cases  the  seed  for  the  different  plats  was  obtained  from 
different  seedsmen,  in  order  to  compare  the  varieties  from  various 
sources. 

April  13  and  14,  1894,  varieties  of  potatoes  were  again  planted, 
this  time  108  different  kinds.  A  few  of  those  planted  in  1893  were 
omitted,  while  a  few  new  ones  were  added  to  the  list. 

Each  season  the  planting  was  begun  as  soon  as  the  ground  was  in 
first  rate  condition  for  planting  and  there  was  promise  of  sufficiently 
settled  weather  to  allow  all  the  planting  to  be  done  at  once. 

The  plats  were  of  one  row  each,  varying  in  length  from  four  to 
six  rods.  The  rows  were  3^  ft.  apart.  These  were  furrowed  out  to  a 
depth  of  4  inches  as  nearly  as  could  be  done.  The  potatoes,  usually  cut 
to  two  eyes,  were  then  planted  in  drills  as  nearly  as  possible  one  foot 
apart.  The  ground  was  kept  clean  by  frequent,  nearly  level,  shallow 
cultivation. 

The  seasons  each  year  were  exceptionally  dry  at  a  time  when  the 
potatoes  needed  rain  to  mature  them  properly  and  they  were  also  more 
or  less  attacked  by  a  form  of  leaf  blight,  causing  the  plants  to  die  before 
the  tubers  were  matured.  The  early  varieties  seem  to  start  in  the  spring 
with  more  vigor  than  the  late  ones  and  the  leaf  blight  has  so  far  ap- 
peared to  be  worst  on  the  varieties  which  are  making  the  rankest 
growth  at  the  time  the  attack  begins. 

In  the  following  table  the  yields  of  the  various  varieties  are  given 
for  the  years  1892,  1893,  and  1894.  In  1892  there  were  only  two  vari- 


i895.] 


POTATO    EXPERIMENTS,   1892-3-4. 


121 


eties  planted  in  more  than  one  plat.  These  plats,  however,  were  only 
a  short  distance  apart  and  the  soil  so  far  as  could  be  judged  was  quite 
uniform.  In  1893  more  than  one  plat  was  planted  of  37  varieties.  In 
all  cases  where  more  plats  than  one  of  a  variety  were  planted  the  plats 
were  side  by  side,  and  being  of  a  single  row  each  there  could  be  very 
little  difference  in  the  soil.  The  seed,  however,  for  each  plat  was  from 
a  different  source  and  the  difference  in  yields  is  sometimes  remarkable. 
This  will  be  discussed  under  change  of  seed. 

In  1894  where  there  are  two  plats  they  were  planted  in  different 
parts  of  the  field.  In  cases  where  there  are  four  plats  two  of  them  were 
planted  in  one  place  and  two  in  another,  so  that  for  this  year  much  of 
the  variation  may  be  attributed  to  difference  in  soil,  since  the  seed  for  all 
the  varieties  except  Acme,  Columbus  and  new  banner  was  from  home 
grown  seed. 

The  following  table  gives  the  yield  of  the  different  varieties  tested 
for  the  years  1892  to  1894.  In  judging  of  yields  it  will  be  remem- 
bered that  the  soil  here  is  a  rich,  black,  prairie  soil,  which  has  not  gen- 
erally been  considered  a  good  potato  soil. 

YIELDS  OF  POTATOES,  1892,   1893,  1894. 


Variety. 

Yield  in  bu.  per 
acre,  1894. 

Yield  in  bu.  per 
acre,  1893. 

Yield  in  bu.  per 
acre,  1892. 

Total. 

Mer- 
chant- 
able. 

Total. 

Mer- 
chant- 
able. 

Total. 

Mer- 
chant- 
able. 

Acme  

59-5 

42 

"3-5 
78.5 
126 

72 
91-5 

46.5 
27.5 
95-5 
66 

99 
58 
67-5 

Alexander's  No.,  i        

54-5 

37-5 

Alexander's  prolific         

53 
50.5 
23 
54 
31-5 
83 

43-5 
35-5 
15.5 
39-5 
22.5 

65-5 

1  60 

143.5 

American  giant  

103.5 

92-5 

99-5 
103.5 
9i 
61 

57 
74 
78.5 
64.5 
121.5 
126 
104.5 
112.5 
114 
88.5 
80.5 
82.5 
9i 
103.5 
82 
109.5 
70 
84.5 

70 
72.5 
64-5 
42 
42 
55-5 
45 
32 
88.5 

87 
73 
80.5 

79-5 
54-5 
51-5 
53 
80.5 
87 
66 

94 
44 
43-5 

Arizona           

70 
45 
34  5 

55-5 
31-5 
23-5 

103.5 

89 

Badger  state  

193-5 

170 

Badger  state  peachblow  .... 

21.5 

ii 

Baker's  seedling  

76.5 

57 





Barstow  .    ...        ...        

49 

39-5 

Beauty  of  Hebron  

72 
46.5 

50 
32.5 

165.5 

136 

Boley's  northern  spy                   .  . 

78 
58 

63 

48 

Brownell's  31             

66.5 

40 

122 


BULLETIN    NO.    40. 

YIELD  OF  POTATOES,   1892,   1893,   1894 — Continued. 


[April, 


Variety. 

Yield  in  bu.  per 
acre,  1894. 

Yield  in  bu.  per 
acre,  1893. 

Yield  in  bu.  per 
acre,  1892. 

Total. 

Mer- 
chant- 
able. 

Total. 

Mer- 
chant- 
able. 

Total. 

Mer- 
chant- 
able. 

Brownell's  winner           

105 
148 
128.5 
170.5 
152.5 
171 

105-5 

101 

120.5 
151 
125-5 
128 
164 
107 

87 
66.5 
88.5 
82 
70 

71-5 
124.5 
160.5 
78 

85 
90 
86 
89 
99-5 
64.5 
78 
114 
76 
66.5 
70 
80.5 
119 

55-5 
70.5 

132 

150 
103 
155 
89.5 
1  08 

81 
108.5 

95 
128.5 
112.5 

122 

73 
70 

94 
H5.5 
99-5 
93 
135 
95 
61 

51-5 
53 
44 
46.5 

41-5 
83.5 
117.5 

67.5 
80 

58.5 
62.5 

65 
68.5 

45 
64 
98 
48 
17 

22 
58.5 

99 
42.5 
58.5 
75-5 
1  06 
78 
128.5 
72 
9i 

36.5 
48.5 

26 
34 

Burbanks  

45-5 

34-5 



Burpee's  extra  early  

46 

29-5 

Burpee's  superior   

28 
36.5 

21 

29 

135 

114 

Carman  

Cayuga  .  . 

22.5 

14.5 

Chas.   Downing  

49 
36.5 

25.5 
19.5 

Cheeseman  

66 

41 

Chicago  Market  

58 

48.5 

Clark's  No.  i   

93-5 

68.5 

Columbus  

Crown  jewel  . 

58.5 
73 

36 

52 

Cow  horn  

24 

6 

Crane's  Juneating  

67 

48.5 

Cream  City  

32.5 

2l' 

Dandy  

82.5 
52.5 
48 
72.5 
63 
53 
36.5 
67 

55-5 
24 

64 
40.5 
33-5 
60.5 

54 
46 
30.5 
64.5 
48 
18 

Dakota  red  

Delaware  

119 
"5 

94 

IOO 

Dreer's  standard   

170.5 
99 
120.5 
80.5 

95-5 
86 
112.5 
60.5 
77 

148 

74 
98 

58.5 
77 
50 
9i 
42.5 
66 

Early  albino  

73 

52.5 

189 

149 

Early  Essex  

44 

26.6 

Early  Illinois  

40 

3i-5 

Early  market  

61.5 
43 

47 
33-5 

i895.] 


POTATO  EXPERIMENTS,  1892-3-4. 


123 


YIELDS  OF  POTATOES,   1892,   1893,   1894 — Continued. 


Variety. 

Yield  in  bu.  per 
acre,    1894. 

Yield  in  bu.  per 
acre,    1893. 

Yield  in  ba.  per 
acre,    1892. 

Total. 

Mer- 
chant- 
able. 

Total. 

Mer- 
chant- 
able. 

Total. 

Mer- 
chant- 
able. 

Early  Oxford  

91.5 
120.5 

53 
79-5 

36.5 

23 

81 

7i 

Early  Ohio  

2OI  .5 

165 

Early    Puritan  

57 
"5-5 
74 
138 
84-5 
121.5 

77 
169.5 
61 

38 
93 
38.5 
115.5 

59-5 
93 
52 
133-5 
40 

29-5 
31-5 
19-5 

22 

19.5 
10 

Early  sunrise     

Early  Walton  

23 

12 

17-5 
19-5 
15 
68.5 

32-5 
45 

12 

8 

10 

52.5 
28 

35-5 

216 

186* 

Early  Wisconsin  

Empire  State  

Everett  ....              4  

63-5 
"3-5 

IOI 

131 
68.5 

75-5 
72.5 

56 
70 
162.5 
"3-5 
157-5 
143 
105.5 
100.5 

35-5 
86 

78.5 
85 
37 
48 
45 
27-5 
43-5 
139 
8i-5 
"9-5 
"5-5 
70.5 
66 

38 

3i 

Freeman  

30.5 
34 

15.5 
17 

Garfield  

28.5 

18 

Gen.  McLellan  

64 
89.5 

57-5 
78.5 

Golden  beauty  

48 

38.5 

Howe's  premium   

4i 
35-5 
57-5 
105 

35 
26.5 

45-5 
84 

Grange  

157-5 
188.4 
70 
75-5 
82.5 
112.5 
100.5 

99 
81 
80.5 
88.5 
78 
95-5 
139-5 
38.5 
37 
95-5 
96.5 

37 
67.5 

58.5 
64-5 

105-5 
124.5 

13 
28 

46.5 
81 
98 
75-5 
46.5 
40 

63-5 
68.5 

78.5 
105.5 
21.5 
29-5 
64.5 
67.5 
25 
53-5 
38  5 
43-5 

Harbinger  .    . 

34 

15 

Kings  Co.  mammoth     

72.5 

61.5 

Koshkonong   

59-5 

48.5 

Lee's  favorite  

1 

83 
50.5 
48.5 

68.5 
39 
44 

I7I.5 

146.5 

Manitoba  rose  

Martin's  seedling.  ..          

79-5 

68 

M3-5 

"3-5 

Maggie  Murphy  

52-5 

43-5 

Monroe  

40 

29 

Monroe  Co.  pride  

32 

22.5 

Monroe  Co.  pride  

27 
17 
15-5 

77-5 

21 

10-5 
10 
60.5 

Nevada  .... 

119 
i35 

87.5 
93 

124 


BULLETIN    NO.    40. 


[April, 


YIELD  OF  POTATOES,   1892  1893,   1894 — Continued., 


Variety. 

Yield  in  bu.  per 
acre,  1894. 

Yield  in  bu.  per 
acre,    1893. 

Yield  in  bu.  per 
acre,  1892. 

Total. 

Mer- 
chant- 
able. 

Total. 

Mer- 
chant- 
able. 

Total. 

Mer- 
chant- 
able. 

New  queen  

78.5 
"5 
66.5 

101 

83.5 
5i.5 
58.5 
54 
93 
74 
103 

56 
83.5 
51-5 
79-5 
52 
34-5 
45 
30.5 
67-5 
43-5 
74 

32 

27 

Nott's  victor..  

84.5 

65.5 

New  banner  

Ohio  junior  

43-5 
25-5 
43-5 

34 

20 
28.5 

156 

135-5 

Paris  rose  

122.5 

116. 

Pearl  of  Savoy  

5i 
26 

63 
54-5 

39-5 
2O.5 

39-5 
49-5 

163.5 
108  5 

136.5 
93- 

People's..                       .            

82.5 
68.5 

69 

98.5 
64.5 
17.5 
95-5 
99-5 
68.5 

83.5 
51-5 
81 
109.5 
106 
69 
9i.5 
70.5 
in.  5 

122 
62 

66 

68.5 

96.5 
no 
70 
68.5 
66.5 

"3-5 
1  06 

78 
75-5 
99 
56 
73 
57-5 
79-5 
129.5 

137-5 
66 

78.5 
38.5 
29 
53 
36 

54-5 
40 
40 
74-5 
35-5 
42.5 
78.5 
77 
40 

58.5 
35  5 
67-5 
64-5 
78.5 
55-5 
78 

42 
77 
9i-5 
34-5 
47-5 
.    38.5 
70 

70-5 
42.5 
42.5 
41 
82 

77 
55-5 
53 
66 

35-5 
38.5 
16 

21 
107.5 
II0.5 

53 
54 
6 
none 

44 
26 

Perfect  gem  

52-5 

38 

Polaris  

5i.5 
64 
62 

37-5 
45 
52 

Pootatuck  

56.5 

44 

Potentate  

65.5 

60 

Prince  Edward's  Island  rose  

5i 
77-5 
54 

42.5 

64 
48 

Pride  of  the  field  

Pride  of  the  west  .... 

70 

60.5 

Queen  of  the  valley  

49 
4i 

40 
29 

Quinnipiac  

68 
5i 
24 
36.5 
25-5 
45 
43 

57 
40.5 

12 
23 
19-5 

34-5 
34 

Reed's  86  

M3 

120. 

Rural  New  Yorker  No   2  

130 

114. 

Rogers  seedling   

34 

15.5 

Rough  diamond  

ii-5 

none 

Rural  blush  

37-5 

29 

35-5 

28 

Red  lady  finger   

19.5 

4 

Red  Ohio   

1895-]  POTATO    EXPERIMENTS,   1892-3-4.  125 

YIELD  OF  POTATOES,   1892,   1893,   1894 — Continued. 


Variety. 

Yield  in  bu.  per 
acre,    1894. 

Yield  in  bu.  per 
acre,  1893. 

Yield  in  bu.  per 
acre,  1892. 

Total, 

Mer- 
chant- 
able. 

Total. 

Mer- 
chant- 
able. 

Total. 

Mer- 
chant- 
able. 

Snowflake  

104.5 
72.5 
9i.5 
70.5 
107 
78.5 
58 
56 
71-5 
70.5 

89 
46.5 
70 
48 
86.5 
61 
38.5 
35-5 
48 

43-5 

29 

17 

24 
ii 

119 

IOI. 

State  of  Maine  

57 

46 

Sunlit  star  

37-5 

32 

Signal  

57-5 

37 

Six  weeks    market  

67 
24 
58 
23 

59 

20 
46 
13.5 

Summit  

88.5 
93 
56 
64-5 
118 
130' 
7i.5 
78 
70 
66.5 

9i 
62.5 

71-5 
70 

74 
52 
62.5 
98.5 
46.5 

77 
82 

157-5 
126 

101 
122 
91-5 

86 
76.5 

54 
54 
25-5 
27.5 

89 
97 
39-5 
5° 
47-5 
45 
5° 
40 
42.5 
44 
39-5 
29 
5° 
69 
28 
50 

59-5 
121.5 
82 
66.5 

IOI 

62.5 
58.5 
50 

Shattuck  s   kidney  

Spaulding  

41.5 

35 

Theoborn  

28 
31-5 

21 
22.5 

Tomnock  

34 

2O.5 

Vick's   extra   early  

18.5 
20.5 

4-5 
8-5 
38 

6.5 
17 
4 
6 
18 

Vaughan  

204 

186. 

Van  Ornam  

12 
10 
12 

White  flour  

7-5 
9-5 

White  orange  

13.5 

10. 

White  star  

10 
7-5 

8 
8.5 
5-5 
17 

3 

5 
5 
6 

3 
M 

White  lily  

White  seedling  

Winslow  

36 
64.5 
57 
74-5 
73 
4i 
38.5 

21 

45 
41 
5° 
49 
28 

24 

Wisconsin  beauty  

World's  Fair  

22 

14-5 

Stray  beauty  

I6.5 
26 

12 

'7-5 

Triumph  

The  potato  varies  remarkably.  The  reply  made  by  one  of  our 
local  potato  growers  when  asked  about  some  new  varieties  he  was 
testing  does  not  seem  to  be  much  too  strong:  "  You  can't  tell  anything 
about  a  potato  the  first  year."  Perhaps  it  might  be  well  to  say  that 
results  for  the  second  and  third  year  make  the  conclusion  only  so  much 
less  uncertain. 


126  BULLETIN    NO.    40.  [Apri,, 

Descriptions  were  made  of  the  varieties  as  grown  in  1892,  1893, 
and  1894.  The  later  descriptions  were  made  without  consulting  the 
earlier,  and  it  is  found  that  they  often  disagree  in  important  characters. 
The  conditions  of  season  seem  to  make  a  difference,  not  in  yield  alone, 
but  in  appearance,  form,  and  quality  of  the  tubers  as  well.  Tubers  of 
the  same  variety  have  seemed  to  differ  widely,  too,  in  the  same  season. 
This  is  especially  noticeable  in  the  character  of  the  flesh  of  the  potato, 
which  will  often  vary  in  color  from  white  to  yellowish  white,  in  grain 
from  fine  to  coarse,  and  in  texture  from  tender  and  crisp  to  tough  or 
hard,  becoming  harsh  to  the  touch.  Not  unfrequently  tubers  will  be 
found  in  a  variety  that  have  a  decidedly  sweetish  taste.  In  many  cases 
the  individual  tubers  of  a  variety  will  be  found  to  differ  more  from 
each  other  than  two  varieties  will  when  taken  as  a  whole. 

Testing  varieties  has  received  more  attention  at  the  hands  of 
station  workers  than  any  other  phase  of  potato  culture,  and  the  sum  of 
their  results  seems  to  be  that  the  standard  varieties  are  at  least  the 
safest  for  the  general  planter.  Occasionally  a  new  kind  comes  out 
that  in  one  or  more  respects  is  superior  to  some  of  the  old  ones,  but  it 
scarcely  seems  possible  to  find  all  the  virtues  combined  in  one  variety 
to  such  an  extent  that  it  is  without  question  the  potato.  Perhaps 
the  most  extensive  experiments  with  varieties  have  been  carried  on  at 
the  following  stations: 

Indiana,  through  four  seasons;  Michigan,  six  seasons;  Wisconsin, 
six  seasons;  Kentucky,  four  seasons;  Ohio,  seven  seasons,  and  Missouri, 
two  seasons.  Summing  up  all  the  results  from  the  above  stations,  the 
following  named  varieties  are  among  the  most  productive  sorts: 

Alexander's  prolific,  Early  harvest, 

Beauty  of  Hebron,  Early  Ohio, 

Burbank,  Howe's  premium, 

Charter  oak,  New  queen, 

Clark's  No.  i,  Pearl  of  Savoy, 

Dakota  red,  Rural  New  Yorker  No.  2, 

Dictator,  Rural  blush, 

Early  sunrise,  Summit, 

Early  king,  Thorburn, 

Empire  state,  White  elephant. 

Early  Oxford, 

In  looking  over  the  station  reports  it  is  found  that  there  are  no 
two  agreeing  in  their  estimates  as  to  which  is  best,  and  usually  the  same 
station  does  not  agree  with  itself  two  years  together.  The  potato 
seems  to  be  so  variable  and  so  sensitive  to  the  conditions  under  which 
it  is  grown  that  about  the  only  recommendation  which  it  is  safe  to  make 
would  be  to  adhere  to  the  standard  varieties,  at  least  for  the  main  crop. 


POTATO  EXPERIMENTS,  1892-3-4. 


Comparison  of  Seed  from  Different  Sources. 

There  is  a  widespread  belief  among  farmers  that  it  is  best  to 
change,  occasionally,  seed  of  all  kinds  of  crops.  There  is  not  much 
doubt  but  that  in  many  cases  it  is  better  to  change  seed,  but  it  must 
have  its  limitations.  Along  with  our  test  of  varieties  some  comparison 
has  been  made  of  potatoes  from  different  sources  for  seed,  but  it  will 
not  do  to  interpret  results  too  closely.  The  following  table  will  give 
the  varieties  compared  and  the  source  of  seed  in  each  case: 

COMPARISON  OF  YIELDS  FROM  SEED  FROM  DIFFERENT  SOURCES. 


Variety. 

Old's 
seed. 

Home 
seed. 

Variety. 

Vaugh- 
an's  seed 

Home 
seed. 

American  giant  

23 

31.5 

Alexander's  prolific.  .  .. 

50.5 

c  j 

Charles  Dow«ning  

49 

36.5 

Arizona  

7o 

45 

Crown  jewel  

73 

58.5 

Beauty  of  Hebron,    .  .  . 

72 

46    5 

Dandy  

52.5 

82.  * 

Burpee's  superior   .  . 

28 

^6    5 

Early  market  

43- 

61.5 

Early  Ohio  

31 

1  1  .  5 

Early   Puritan  

31  .5 

29.5 

Early  white  prize  

17.5 

iq   <; 

Howe's  premium  

41 

57-5 

[Empire  state  

68.5 

32    5 

26 

«;i 

i  Freeman     

155 

17 

Polaris  

51.5 

62 

Ohio  junior  

25.5 

43.  c 

Queen  of  the  valley.  .  .  . 

49 

41 

Reed's  86  

36.5 

24 

Signal             

29    5 

57    5 

Rural  New  Yorker 

4  3 

25    1 

Summit  

24 

58 

Snowflake  

2Q 

17 

Thorburn  

28 

31  .  c 

Vaughan 

4    5 

8    « 

Variety. 

Howe's 
seed. 

Home 
seed. 

Variety. 

Old's 

seed. 

Howe's 
seed. 

American  giant  

54 

31  .e 

American  giant           .  . 

27 

54 

Boley's  N.  spy  

58 

78 

Dakota  red  

33-5 

60.  5 

Brownell's  winner  

36.5 

48.5 

Delaware  

53 

63 

Howe's  premium  

35  -5 

57-5 

General   McLellan   .  .  . 

64 

89   5 

Early  Ohio  

29.  5 

11.5 

Howe's  premium  

41 

3c    e 

Pearl  of  Savoy     

63 

51 

Pearl  of  Savoy.  .    . 

26 

63 

Polaris  

64 

62 

Polaris     

51  .  5 

64 

Prince  Edward's  Island 
rose  

51 

77-5 

White  flour  

IO 

12 

Quinnioiac 

SI 

68 

Rural  New  Yorker  .... 

45 

25  5 

Variety. 

Howe's 
DO»I 

Vaugh- 

Old's 

Vaugh- 

Variety. 

seed. 

an's  seed 

Delaware  

63 

36.5 

Porlw  Ohin 

Delaware.  . 

53 

36.  5 

Rural  New  Yorker.. 

29  -5 
45 

31 
43 

In  five  cases  out  of  ten  that  are  comparable  home  grown  seed 
yielded  more  than  seed  from  Howe,  and  the  average  of  the  ten  com- 
parisons is  in  favor  of  the  home  grown  seed  in  the  proportion  100  to  95. 

In  ten  cases  out  of  thirteen  that  are  comparable  home  grown  seed 
yielded  more  than  seed  of  the  same  variety  from  O!d=,  and  the  average 
of  the  thirteen  comparisons  is  in  favor  of  home  grown  seed  in  the  pro- 
portion of  100  to  79. 

In  six  cases  out  of  thirteen  in  which  home  grown  seed  can  be  com- 
pared with  seed  from  Vaughan,  the  home  grown  seed  has  yielded  the 


128  BULLETIN    NO.    40. 

most,  but  the  average  of  the  thirteen  comparisons  is  in  favor  of  Vaughan's 
seed  in  the  proportion  of  100  to  86. 

In  seven  cases  out  of  eight  than  can  be  compared  seed  from  Howe 
produced  more  than  seed  of  the  same  variety  from  Olds,  and  the  average 
of  the  eight  comparisons  is  in  favor  of  Howe  in  the  proportion  of  100 
to  70. 

In  the  one  case  in  which  the  same  variety  was  grown  from  seed 
obtained  of  both  Olds  and  Vaughan  the  comparison  is  as  100  to  69  in 
favor  of  Olds. 

In  three  cases  in  which  the  same  varieties  from  Howe  and  Vaughan 
were  planted  seed  from  Howe  yielded  more  than  that  from  Vaughan 
in  two  cases,  and  the  average  of  the  three  comparisons  is  in  favor  of 
Howe  in  the  proportion  of  100  to  80. 

As  a  result  of  these  comparisons  we  have  home  grown  seed  yield- 
ing more,  on  an  average,  than  seed  from  either  Howe  or  Olds,  but  less 
than  seed  from  Vaughan,  while  seed  from  Vaughan  has  yielded  de- 
cidedly less  where  it  could  be  compared  than  seed  from  either  Olds  or 
Howe. 

In  four  varieties  the  same  seed  was  from  Olds,  Howe,  and  home 
grown.  In  one  of  the  cases  home  grown  seed  stood  at  the  head  of  the 
list  and  in  the  other  three  cases  it  was  second.  In  three  cases  Howe's 
seed  stands  at  the  head  of  the  list  and  in  the  other  it  is  at  the  foot.  In 
one  case  Olds'  seed  stands  second  in  the  list  and  in  the  other  three  cases 
it  is  at  the  foot. 

Seed  from  each  plat  of  fifteen  of  these  varieties  which  have  been 
compared  in  this  way  for  1893  was  saved  and  again  planted  side  by  side 
in  1894  and  in  twelve  cases  out  of  the  fifteen  seed  from  the  plat  giv- 
ing the  best  yield  in  1893  also  gave  the  best  yield  in  1894. 

In  plats  arranged  as  these  were,  only  a  single  row  each,  and  only 
three  and  one-half  feet  apart  very  little  allowance  can  be  made 
for  difference  in  soil.  Perhaps  the  only  conclusion  that  can  be  drawn 
from  the  comparisons  is  that  some  character  or  condition  of  the  seed, 
which  we  do  not  yet  understand,  must  make  a  large  difference  in  crop. 
But  it  will  not  do  to  say  that  seed  from  one  place  is  necessarily  superior 
to  seed  from  another. 

In  general  the  northern  states  seem  better  adapted  to  the  growth 
of  the  potato  than  the  southern;  but  there  are  local  modifying  causes, 
such  as  the  character  of  the  soil  and  season,  insects,  fungus  diseases  and 
the  growers'  general  care  of  his  crop.  I  believe  it  would  be  possible 
for  the  potato  growers  of  this  state  so  to  manage  that  change  of  seed 
would  be  of  but  little  advantage.  In  fact  the  average  result  of  experi- 
ments in  this  line  leaves  it  an  open  question  as  to  whether  there  is  or  is 
not  a  benefit  from  changing  seed  so  as  to  have  new  seed  of  the  same 
variety  but  from  a  new  source. 

Perhaps  the  most  extensive  work  in  studying  the  effects  of  change 
of  seed  has  been  done  at  the  Vermont  and  Maryland  stations.  Eight 


1895-]  POTATO    EXPERIMENTS     1892-3-4.  129 

varieties  of  potatoes  were  obtained  by  the  Vermont  Station  and  grown 
by  them  one  year.  Seed  from  these  was  then  sent  to  Maryland,  and 
the  same  eight  varieties  were  then  grown  one  year  at  each  place.  Seed 
was  then  exchanged,  Vermont  sending  seed  to  Maryland,  and  Mary- 
land sending  seed  to  Vermont.  As  a  result  we  have  in  1889,  the  fol- 
lowing as  an  average  of  the  eight  varieties: 

In  Vermont,  potatoes  from  Vermont  grown  seed  yielded  in  Ib. 
In  Vermont,  potatoes  from  Maryland  grown  seed  yielded  73  " 
In  Maryland,  potatoes  from  Maryland  grown  seed  yielded  54  " 
In  Maryland,  potatoes  from  Vermont  grown  seed  yielded  62  " 

But  this  result  is  not  uniform,  for  in  four  cases  out  of  the  eight  in 
Vermont  the  seed  from  Maryland  gave  the  best  yield  and  in  Maryland 
their  home  grown  seed  gave  the  best  yield  in  five  cases  out  of  the  eight, 
though  the  average  was  still  in  favor  of  the  Vermont  seed.  The 
Maryland  Station  also  compared  Vermont  seed  with  Maryland  seed  in 
1890  and '189 1,  the  results  in  both  years  being  in  favor  of  the  Vermont 
seed;  in  1890  Vermont  seed  yielded  at  the  rate  of  179  bushels  per  acre 
and  Maryland  seed  at  the  rate  of  97. 15  bushels  per  acre;  in  1891  Ver- 
mont seed  yielded  at  the  rate  of  125.5  bushels  per  acre,  and  Maryland 
seed  at  the  rate  of  88.5  bushels.  In  1892  seed  from  Maine  was  com- 
pared with  Maryland  grown  seed.  The  result  was  95.5  bushels  per 
acre  from  the  home  grown  seed,  and  72.6  bushels  ->er  acre  from  the 
Maine  seed. 

Georgia  Experiment  Station,  in  bulletin  No.  8,  1890,  says  "home 
grown  seed  gave  slightly  higher  yields  than  that  imported  from  the 
North." 

Louisiana  Experiment  Station,  bulletin  No.  4  (new  series),  1890, 
says  "western  grown  potatoes  are  as  good  for  seed  as  those  grown  in 
the  East.  Home  grown  seed  is  as  good  as,  if  not  superior  to,  either." 

Missouri  reports  a  comparison  of  home  grown  and  northern  grown 
seed  in  1890,  with  twenty-seven  varieties  and  the  result  as  a  whole  was 
in  favor  of  the  home  grown  seed  in  the  proportion  of  100  to  98. 

In  New  York  a  single  trial  did  not  favor  the  practice  of  changing 
seed. 

In  considering  these  statements  in  regard  to  results  of  change  of 
seed  as  found  in  this  way,  it  must  be  remembered  that  at  the  sta- 
tions potatoes  are  grown  under  better  conditions  than  are  generally 
found  in  farm  practice. 

Seed  from  Best  or  Poorest  Hills. 

No  one  has  dug  many  potatoes  without  noticing  the  difference  in 
individual  hills.  One  will  yield  a  few  very  large  and  a  few  small 
tubers,  another  will  be  uniform  in  size  and  all  large,  and  still  another 
will  be  nearly  all  small.  Some  experiments  have  been  made  to  see  if 
these  characters  could  be  perpetuated.  Hills  containing  all  large  and 
others  containing  all  small  potatoes  have  been  saved  and  planted  side 


130  BULLETIN    NO.   40. 

by  side.  This  line  of  work  has  been  carried  on  at  three  different  sta- 
tions, and  though  it  has  not  gone  far  enough  to  prove  conclusively  that 
there  is  an  advantage  in  selecting  the  best  hills,  the  results  point  in  that 
direction. 

Trials  with  eleven  varieties  at  the  Geneva,  New  York,  Station,  re- 
sulted in  favor  of  seed  that  had  been  selected  from  the  best  hills.  In 
another  trial  at  the  same  Station  with  116  varieties  in  garden  tests  the 
largest  yields  were  obtained  in  69  cases  from  the  largest  seed  that  could 
be  selected  from  the  best  hills  of  the  previous  years'  crop,  while  in  38 
cases  the  reverse  was  true. 

Digging  Potatoes  late  and  early  for  seed:  Second  crop. 

The  Kansas  Station  made  comparisons  for  two  seasons  of  the  value 
for  seed  of  potatoes  dug  early,  of  those  dug  late,  and  of  those  grown  as 
a  second  crop.  (By  second  crop  is  meant  that  the  potatoes  were  dug 
early  and  planted  at  once,  making  a  second  crop  the  same  season). 
They  conclude,  first,  that  there  is  nothing  gained  in  earliness  by  using 
second  crop  seed;  second,  that  there  is  a  positive  gain  in  amount  of 
product,  as  well  as  size  of  tubers,  over  that  of  first  crop  seed  grown  in 
the  same  locality;  third,  that  firm,  well  kept,  unsprouted  seed  is  better 
than  that  which  is  sprouted  and  shriveled,  giving  a  heavier  product  of 
better  size  and  quality.  Growing  a  second  croo  is  not  recommended, 
except  in  localities  where  the  seasons  are  long. 

The  size  of  seed  pieces  to  plant. 

The  size  of  seed  pieces  to  be  planted  has  received  more  attention 
than  any  other  phase,  except  the  test  of  varieties.  Twenty  stations 
have  carried  on  large  numbers  of  experiments,  and  the  general  conclu- 
sion reached  is  that  the  larger  the  seed  pieces  the  greater  the  yield. 
This  is  so  decidedly  true  that  in  the  average  of  trials  made,  good-sized 
whole  potatoes  have  yielded  nearly  twice  as  much  as  potatoes  cut  to 
one  eye,  and  there  has  been  nearly  a  uniform  gradation  in  the  crop  as 
the  size  of  seed  passed  from  good-sized  whole  potatoes  through  halves, 
quarters,  three-eye  pieces,  two-eye  pieces,  to  one-eye  pieces,  and  the 
result  has  fallen  still  lower  when  peelings  have  been  planted  for  com- 
parison. As  a  specimen  of  the  reports  made,  this  from  Ohio  is  given. 
It  is  an  average  of  two  years'  results. 

One  eye  pieces  yielded  1 15  bushels  per  acre. 

Two-eye  pieces       "        180      "  "       " 

Half   potatoes          "       226      «  "       " 

Whole  potatoes      "       255      "          "       " 

The  following  conclusions  are  deduced  from  all  of  the  work  done 
at  the  Ohio  station  on  the  subject  of  cutting  seed: 

"  The  marketable  product  increases  as  the  size  of  the  cutting  is 
increased,  but  does  not  follow  the  same  ratio  as  the  total  product,  the 
rate  of  gain  being  less." 


1895-]  POTATO    EXPERIMENTS,     1892-3-4.  IJI 

''  The  increase  is  found  in  both  the  large  and  small  potatoes,  the 
greater  portion  being  in  the  latter." 

"  A  crop  grown  from  whole  potatoes  matures  at  an  earlier  date 
than  from  small  cuttings." 

"  Small  cuttings  require  soil  that  is  more  highly  enriched  and 
thoroughly  prepared  than  large  cuttings  and  whole  potatoes  in  order  to 
secure  a  good  stand  and  to  produce  a  profitable  crop." 

"  The  question  of  relative  profit  as  between  the  use  of  small  cut- 
tings and  whole  potatoes  depends  upon  the  cost  of  seed  potatoes,  the 
date  at  which  the  crop  is  to  be  harvested  and  sold,  and  the  condition  of 
the  soil  at  planting  time." 

"  In  ordinary  practice  it  will  usually  be  found  that  neither  extreme 
as  to  quantity  of  seed  used  will  be  profitable.  The  safest  plan  is  to 
use  large,  well-matured,  healthy  potatoes,  and  cut  to  two  and  three 
eyes."  .  . 

In  contrast  with  the  results  which  are  so  overwhelmingly  in  favor 
of  heavy  seeding  may  be  mentioned  the  following  exceptions:  In  a 
trial  at  the  New  York  Station  there  was  practically  no  difference  in 
yield  between  cuttings  and  whole  potatoes.  In  Oregon  one-eye  pieces 
yielded  more  than  two  or  three  eye  pieces  or  whole  potatoes.  Two 
experiments  out  of  three  at  the  West  Virginia  Station  favored  one- eye 
pieces,  and  in  one  trial  the  yield  was  30  per  cent,  greater  with  single- 
eye  pieces  than  with  whole  tubers. 

Mr.  Terry,  of  Ohio,  says  he  never  uses  larger  than  one-eye  pieces 
for  planting,  and  yet  his  average  yield  for  a  number  of  years  has  been 
nearly  two  hundred  and  fifty  bushels  per  acre,  while  the  average  for 
the  state  is  below  seventy-five  bushels.  He  says  he  cannot  afford 
either  the  labor  of  handling  more  seed,  or  to  put  more  money  into 
seed ;  and  while  his  fields  look  poorer  early  in  the  season  than  those 
of  his  neighbors,  they  soon  improve  and  eventually  yield  more. 

He  does  not  depend  for  his  crop  on  the  amount  of  seed  planted, 
but  on  the  thorough  preparation,  cultivation  and  fertilization  of  his  soil. 

Before  deciding  on  the  amount  of  seed  to  plant,  we  must  consider 
the  cost  of  seed  potatoes  as  compared  with  those  for  the  general  mar- 
ket. The  amount  of  seed  needed  for  an  acre,  if  whole  large  tubers 
were  planted,  would  be  from  30  to  40  bushels,  while  for  single  eye- 
pieces from  3  to  4  bushels  is  sufficient. 

The  reasons  for  the  larger  yield  from  the  larger  seed  are:  A  greater 
number  of  plants  are  formed;  these,  having  a  greater  proportional 
amount  of  seed  to  each  one,  make  a  more  rapid,  vigorous  growth  at 
first  and  ripen  earlier,  and  at  least  partly  escape  the  summer  drought 
and  the  effects  of  leaf  blight.  An  early  drought  followed  by  favorable 
weather  may  occasionally  give  a  larger  yield  from  small  seed. 

The  difference  in  time  of  maturity  of  potatoes  from  large  whole 
potatoes  and  single  eye  pieces  is  variously  estimated  at  from  one  to  two 
weeks,  and  where  potatoes  are  wanted  for  early  market  it  may  pay  to 


132  BULLETIN    NO.     40.  [April, 

plant  the  extra  amount,  but  for  the  general  field  crop  the  common 
practice  of  cutting  to  two  eyes,  except  where  the  eyes  are  very  close 
together,  will  be  found  the  best.  This,  however,  would  not  seem  to 
hold  where  exceptional  fertilizing  and  care  are  given. 

Experiments  'with  Different  Parts  of  the  Potato  for  Seed. 

There  has  been,  for  a  long  time,  more  or  less  theorizing  as  to 
whether  it  is  best  to  use  the  stem  end,  the  middle,  or  the  seed  end  of  the 
potato  for  planting.  As  a  result  of  a  large  amount  of  work  done  at  ten 
of  our  experiment  stations,  the  conclusion  is  reached  that  it  makes  no 
difference.  As  an  illustration  of  the  contradictory  results,  the  following 
may  be  given: 

A  summary  of  trials  for  three  years  at  the  Michigan  station  shows 
the  greatest  yield  of  marketable  tubers  from  seed  end,  next  largest  yield 
from  stem  end;  while  at  the  New  York  Station  a  large  number  of  trials 
indicate  that  the  central  portion  of  the  potato  is  best  for  seed.  In  Utah 
the  results  for  two  years  were  in  favor  of  planting  the  stem  end;  In 
Wisconsin  the  removal  of  the  seed  end  from  the  potato  showed  no 
advantage  in  yield.  In  Indiana  (Bull.  34,  1891)  the  seed  end  of  the 
potatoes  yielded  74  bushels  per  acre,  middles,  107  bushels  per  acre,  and 
stem  ends  94  bushels  per  acre.  In  Colorado  (Bull.  4,  1888)  seed  ends 
of  potatoes  yielded  344  bushels  per  acre,  while  stem  ends  yielded  290 
bushels  per  acre.  In  this  way  the  results  from  the  different  stations 
neutralize  each  other. 

Time  of  Planting. 

The  question  of  time  of  planting  in  its  relation  to  yield  has  scarcely 
been  considered  in  the  way  of  direct  experiment.  There  seems  no  rea- 
son to  doubt,  however,  that  with  rare  exceptions  the  earlier  the  planting 
is  done  the  better  will  be  the  crop.  The  late  planting  is  too  apt  to  be 
cut  off  by  hot,  dry  weather  and  the  leaf  blight.  Late  varieties,  too, 
have  been  almost  driven  out  of  the  field  on  account  of  the  leaf  blight 
and  the  uncertainty  of  having  seasonable  weather  for  growing  and  ma- 
turing the  crop. 

Depth  of  Planting. 

Depth  of  planting  potatoes  has  been  made  a  subject  of  study  at 
five  experiment  stations.  The  results  have  been  somewhat  contradictory 
but  with  the  greater  number  of  trials  turning  out  in  favor  of  compara- 
tively shallow  planting.  In  Michigan  the  results  for  1890  and  1891 
were  in  favor  of  planting  one  or  two  inches  deep  rather  than  three, 
four  or  five,  while  in  1893  the  planting  five  inches  deep  gave  the  best 
results. 

From  Utah  the  statement  comes  that  "  the  depth  of  planting  did 
not  materially  affect  the  total  yield  of  potatoes;"  but  "potatoes  planted 
near  the  surface  contained  23.1  per  cent,  more  starch  than  those  planted 


1895-]  POTATO    EXPERIMENTS,    1892-3-4.  133 

deeper."     In  the  greater  number  of  trials  the  best   results  have   come 
from  planting  two  to  three  inches  deep. 

Distance  Apart  for  Planting  Potatoes. 

This  has  been  made  a  subject  of  study  in  eight  states,  and  the 
average  of  the  results  goes  to  prove  the  common  practice  among  far- 
mers to  be  correct.  Hills  have  seldom  given  as  good  yields  as  drills. 

In  drilling  potatoes  Michigan  makes  a  distinction  between  planting 
whole  potatoes  and  pieces,  and  recommends  for  single  eyes  twelve  to 
fifteen  inches  apart,  for  half  potatoes,  two  feet  apart,  and  for  whole 
potatoes  two  and  one-half  feet  apart. 

Ohio  says  results  show  that  rows  should  be  from  two  and  one-half 
to  three  feet  apart  and  the  hills  one  foot.  This  is  supposing  one  or  two 
eye  pieces  are  used  for  seed.  In  thirty-two  trials  of  hill  as  compared 
to  drill  planting  in  Michigan  the  results  were  in  favor  of  drills. 

The  New  York  Experiment  Station,  at  Geneva,  reports  in  favor  of 
drill  planting. 

Wisconsin  has  found  no  material  difference  between  hills  and  drills. 

Cultivation. 

In  a  large  number  of  experiments  at  twelve  different  stations,  com- 
parisons have  been  made  of  methods  of  cultivating  potatoes.  Seasons 
vary  so  much  that  the  results  of  different  methods  are  continually  con-- 
tradicting  each  other.  One  season  potatoes  mulched  will  yield  two  or 
three  times  as  much  as  those  grown  in  the  ordinary  way,  and  the  next 
year  the  results  will  be  almost  the  opposite.  In  trials  where  direct  com- 
parisons were  made,  results  from  Alabama,  Kansas,  and  Utah  favor 
flat ,  while  Indiana  favors  ridge  cultivation.  Maryland,  New  York  and 
Ohio  report  practically  no  difference  in  yield  between  flat  and  ridge 
culture.  Vermont  reports  that  in  one  season's  trial  mulching  when  four 
inches  high,  gave  better  results  than  ridging.  Results  obtained  at  the 
stations  in  Colorado,  Indiana,  Michigan,  and  New  York  are  against 
mulching.  The  general  tendency  seems  to  be  toward  thorough  prepa- 
ration of  soil,  and  level  culture. 

Comparisons  of  deep  and  shallow  cultivation  have  been  made  at 
the  Michigan  and  Utah  stations,  with  very  different  results.  In  forty- 
five  trials  at  the  Michigan  station,  the  yield  of  marketable  tubers  was  in 
forty  cases  in  favor  of  deep  culture,  while  in  Utah  shallow  culture  gave 
a  greater  yield  than  deep.  Results  are  so  conflicting  that  no  conclusions 
can  as  yet  be  drawn. 

Commercial  Fertilizers  on  Potatoes. 

Beginning  with  1893  some  work  has  been  done  in  testing  the 
effects  of  commercial  fertilizers  on  the  potato.  Plats  two  rods  square 
were  laid  out  with  a  space  of  eight  feet  between  them  in  the  direction 
in  which  plowing  and  cultivation  was  done.  In  the  other  direction  no 


'34 


BULLETIN    NO.    40. 


[AprtZ, 


space  was  left.  The  experience  at  this  Station  with  commercial  fertil- 
izers on  other  crops  is  that  they  are  of  no  appreciable  benefit  and  the 
result  with  potatoes  has  been  the  same.  While  the  yields  of  the  plats 
varies  greatly,  there  is  no  variation  that  can,  with  certainty,  be  attributed 
to  the  use  of  the  fertilizers.  But  the  results  here  are  not  to  be  taken  as 
conclusive  for  all  parts  of  the  state.  Soils  of  different  places  have  dif- 
ferent requirements  and  must  have  different  treatment.  There  is  no 
way  of  determining  in  advance  what  fertilizing  element  or  elements 
will  and  what  will  not  benefit  a  crop.  The  only  way  to  find  out  is  by 
trying. 


NORTH. 


No   4. 

No.  3. 

No.  2. 

No.  i. 

Sulphate   of   pot- 
ash, 200. 

Nothing. 

Acid    phosphate, 
360. 

Nitrate    of    soda, 
200. 

No.  8. 

No.  7. 

No.  6. 

No.  5. 

Nitrate   of    soda, 
200.     Acid    phos- 
phate,   360.      S  u  1  - 
phate  of  potash, 

Acid     phosphate, 
360.      Sulphate    of 
potash,  200. 

Nitrate   of    soda, 
200.      Sulphate    o  f 
potash,  200. 

Nitrate    of    soda, 
200.     Acid    p  h  o  s  - 
phate,  360. 

200. 

No.  12. 

No.  ii. 

No.  10. 

No.  9. 

Lime,  2,000.  Acid 
phosphate,  360. 

Lime,  2,000. 

Nothing. 

Hardwood  ashes, 
2,000. 

No.  16. 

No.  15. 

No.  14. 

No.  13. 

Mapes    tree    and 
vine  fertilizer,  i  ,  ooo. 

Mapes  special  po- 
tato fertilizer,  1,000. 

Hardwood  ashes, 
2,000.       Nitrate   of 

Lime,  2,000.     Ni- 
trate  of   soda,   200. 

soda,  200.     Acid 
phosphate,    360. 
Sulphate  of  potash, 

Acid  phosphate,  360. 
Sulphate  of  potash, 
200. 

200. 

No.  20. 

No.  19. 

No.  18. 

No.  17. 

Nothing. 

Nothing. 

Nothing. 

Nothing. 

I895-] 


POTATO    EXPERIMENTS,    1892-3-4. 


'35 


The  diagram  on  the  opposite  page  shows  the  arrangement  of  plats 
and  the  number  of  pounds  of  fertilizers  per  acre  applied  to  each.  Nos. 
15  and  1 6  had  fertilizers  in  1894  On^y5  on  ^e  other  fertilized  plats 
fertilizers  were  applied  both  in  1893  and  1894. 

At  the  Kentucky  Experiment  Station  (Lexington)  potash,  either 
in  the  form  of  muriate  or  sulphate  has  been  used  profitably  while 
neither  nitrate  nor  phosphate  has  made  very  appreciable  increase  in  the 
yield. 

At  the  Michigan  Experiment  Station  (Lansing)  wood  ashes  gave 
better  results  than  any  of  the  commercial  fertilizers,  while  barnyard 
manure  was  found  better  still.  It  is  entirely  probable  that  in  other 
parts  of  this  state  valuable  results  could  be  had  from  the  use  of  some 
of  the  commercial  fertilizers.  Most  of  the  experiment  stations  in  other 
states  have  found  benefit  in  applying  a  commercial  fertilizer  in  some 
form ;  but  usually  it  is  not  necessary  to  use  a  complete  fertilizer,  because 
it  is  not  usual  for  all  the  three  principal  elements  of  fertility  to  be  lack- 
ing. Not  unfrequently  the  application  of  nitrogen,  or  potash,  or 
phosphorus  alone  in  some  form,  gives  nearly  as  good  results  as  the 
application  of  all  of  them,  and  at  a  decidedly  less  cost. 


TABLE   GIVING    YIELDS    OF    POTATOES   ON    FERTILIZED    PLATS  AND   CHECK    PLATS 
FOR  -1893    AND    1894. 


2 
sT 

Fertilizers. 

S  —  H 
S  a  o 

">  cr  5T 

C    — 

M     •       w< 

oo>O  M. 
«5  n  <L 

«-  "  s 

S  —  H 

q  a  o 
»  o-jr 

C    t-- 
M   *    w* 
00^3  i. 

VO    fD    » 

*  i  £ 

i 

Nitrate  of  soda  

ss  s 

"5V  1 

2 

Acid  pboshate  

56.5 

7O.  5 

9 

46.  5 

96.  S 

Sulphate  of  potash     ....        

43    5 

79 

5 

Nitrate  of  soda  and  acid  phosphate  

66.5 

64 

6 

Nitrate  of  soda  and  sulphate  of  potash  

7S.7 

58 

7 

Acid  phosphate  and  sulphate  of  potash  

57.  5 

97 

8 

Acid  phosphate,  sulphate  of  potash,  and  nitrate  of  soda  

SO 

85 

q 

Hardwood  ashes  ...        

63 

7O 

IO 

Nothing  

73    "i 

62 

II 

Lime                         .    .        .    ...        

46.  S 

91 

12 

S2  .  5 

91  .  S 

13 
!4 

is 

Lime,  nitrate  of  soda,  acid  phosphate,  and  sulphate  of  potash 
Hardwood  ashes,  nitrate  of  soda,  acid  phosphate,  sulph.  potash 
Mapes  potato  fertilizer  (1894  only)  

66 

89 

49-5 

75-5 
85 
104.5 

Tfi 

Mapes  tree  and  vine  fertilizer  (1894  only)  

56.5 

97.5 

17 

Nothing.  .  .                  

69 

18 

84 

19 

ri 

103.5 

2O 



8l.5 

136  BULLETIN     NO.    40.  \April, 

CONCLUSIONS. 

There  is  so  much  contradiction  in  results  with  potatoes,  that  it  is 
difficult  to  draw  definite  conclusions. 

In  varieties,  it  is  at  least  safest  to  plant  such  as  are  well  known. 
They  are  well  known  because  they  have  proved  generally  satisfactory 
to  growers. 

Changing  seed  from  one  locality  to  another  is  of  doubtful  value. 
The  average  results  are  about  evenly  divided  between  home  grown  and 
foreign  seed. 

In  general,  the  larger  the  seed  pieces  used  the  greater  the  yield 
obtained. 

It  makes  no  difference  what  part  of  the  potato  is  used  for  seed. 

Commercial  fertilizers  at  this  station  have  given  no  profitable 
results,  though  it  is  quite  likely  they  would  in  other  parts  of  the  state, 
especially  the  southern. 

G.  W.  McCLUER,  M.  S., 

Assistant  Horticulturist. 


FUNGOUS  DISEASES  OF  THE  POTATO. 

The  important  position  that  the  potato  holds  in  supplying  food  for 
man  makes  it  necessary  to  protect  it  as  much  as  possible  from  attack  by 
insects  or  fungi.  During  the  last  few  years  considerable  knowledge 
concerning  the  fungous  foes  of  the  plant  has  been  acquired,  and  with 
this  knowledge  have  come  methods  whereby  a  large  part  of  the  dam- 
age usually  inflicted  may  be  prevented.  A  brief  description  is  given  of 
the  diseases  occurring  in  this  state  due  to  fungi,  or  supposed  to  be 
caused  by  them. 

Scab.  The  rough  dead  spots  on  the  surface  of  the  tubers,  known 
as  "  scab,"  are  familiar  to  everyone.  Many  suggestions  have  been 
made,  and  there  has  been  much  discussion  as  to  the  cause  of  this  appear- 
ance. Professor  Thaxter,  while  connected  with  the  Experiment  Sta- 
tion at  New  Haven,  Connecticut,  was  the  first  to  find  the  real  cause. 
By  careful  methods  he  was  successful  in  growing  artificially  a  fungus 
obtained  from  scabby  potatoes,  and  from  pure  cultures  of  this  he  suc- 
ceeded in  producing  the  disease  on  healthy  tubers  at  the  places  inocu- 
lated. Since,  his  experiments  have  been  repeated  at  other  stations,  and 
similar  results  and  conclusions  have  been  reached.  To  the  fungus  thus 
causing  the  disease,  he  gave  the  name  Oospora  scabies.  While  this 
fungus  is  the  active  cause  of  the  disease,  other  forms  are  sometimes 
found  associated  with  it,  and  may,  no  doubt,  help  in  a  slight  way  to  in- 
crease the  damage. 


1895-]  FUNGOUS    DISEASES    OF    THE    POTATO.  137 

Professor  Bolley,  of  North  Dakota,  also  having  made  a  careful 
study  of  this  subject,  has  found  that  the  disease  may  be  held  in  check 
by  seed  treatment.  Among  the  various  remedies  tried,  he  found  that 
soaking  the  seed  for  one  and  a  half  hours  in  a  solution  of  two  and  a 
fourth  ounces  of  corrosive  sublimate  in  fifteen  gallons  of  water  was  the 
most  successful.  This  treatment  has  been  tested  in  quite  a  number  of 
different  places,  and  has  been  found  to  be  very  satisfactory.  It  might, 
however,  be  better  to  soak  the  seed  whole  for  three  hours,  as  the  former 
time  has  not  proved  sufficient  in  some  cases  to  prevent  entirely  the 
disease.  This  treatment  should  be  given  in  wooden  or  earthen  vessels, 
as  metal  is  corroded  by  the  chemical  used.  (While  one  should  remem- 
ber that  corrosive  sublimate  is  a  deadly  poison,  there  is  no  danger 
whatever  in  eating  the  potatoes  that  are  grown  from  seed  thus  treated.) 
It  has  also  been  found  that  treating  seed  and  then  planting  it  on  land 
that  previously  contained  scabby  potatoes  is  not  entirely  successful  in 
preventing  the  disease.  This  is  because  the  fungus  can  exist  in  the 
ground  for  some  time.  It  is  also  claimed  that  drainage  may  carry  the 
spores  from  infected  to  uninfected  land.  The  efficiency  of  the  treat- 
ment is  due  to  the  fact  that  it  is  possible,  by  the  chemicals  used,  to  kill 
the  fungous  spores  on  the  external  parts  of  the  potato  without  injuring 
the  germinative  power  of  the  tuber.  Now  planting  these  seed  free 
from  living  fungous  spores  on  uninfected  land,  there  is  no  danger  of  the 
potatoes  scabbing.  The  results  of  one  year's  trial  at  this  Station  for 
prevention  of  this  disease  are  given  in  the  following  article. 

Potato  scab  is  entirely  a  field  disease,  there  being  no  danger  of 
increase  in  stored  potatoes.  While  it  is  an  injury  not  affecting  the  in- 
terior of  the  tubers,  it  is  quite  detrimental  to  their  appearance  ex- 
ternally, and  thus  affects  their  market  value.  It  has  also  been  found 
that  scabby  potatoes  produce  a  less  yield  per  acre,  and  have  a  greater 
waste  when  used  than  those  not  scabby.  Their  tendency  to  de- 
cay, when  stored,  is  perhaps  also  greater. 

Leaf  Blight.  This  name  is  given  to  that  disease  of  potatoes  which 
early  in  June  begins  to  show  in  brown  dead  patches  on  the  leaves. 
Beginning  usually  at  the  tip  or  margin,  it  slowly  extends  inward,  until, 
in  most  cases,  the  whole  leaf  is  dead.  On  these  dead  areas  has  long 
been  noticed  a  black  mold  known  as  Macrosporium  Solani,  but  whether 
it  caused  the  death  of  the  tissues,  or  was  merely  an  aftercomer,  was  not 
definitely  known.  Mr.  B.  T.  Galloway,  Chief  of  the  Division  of  Vege- 
table Pathology,  Washington,  D.  C.,  claims  to  have  proved  the  specific 
cause  of  the  disease  by  inoculating  experiments  with  this  fungus  on  healthy 
leaves,  and  it  is  now  generally  accepted  by  botanists  that  the  disease  is 
caused  by  this  fungus.  So  far  as  we  have  observed,  the  diseased  con- 
dition of  the  leaves  is  greater  in  dry  than  in  wet  weather.  The  injury 
in  this  disease  affects  the  tubers  only  so  far  as  premature  death  of  the 
foliage  would  decrease  the  yield. 


138  BULLETIN    NO.    40. 

Spraying  experiments  have  been  carried  on  at  a  number  of  places 
to  prevent  this  trouble.  Whether  or  not  the  uniformly  good  results 
thus  accomplished  by  Bordeaux  mixture  are  due  entirely  to  the  preven- 
tion of  leaf  blight,  it  is  at  least  certain  that  sprayed  plants  in  such  cases 
have  given  an  increased  yield  over  plants  unsprayed.  The  benefit  thus 
derived  has  been  very  great  in  some  cases.  The  experiments  conducted 
here  the  past  season  show  that  spraying  with  this  fungicide  caused  an 
increase  of  one-third  the  total  yield,  and  that  the  addition  of  Paris 
green  was  greatly  beneficial.  In  both  cases  spraying  was  helpful,  in 
part  at  least,  because  it  lessened  the  injury  from  potato  bugs.  If  plants 
are  to  be  sprayed  in  this  latitude  to  prevent  the  leaf  blight,  the  first 
treatment  should  be  given  early  in  June.  Bordeaux  mixture  made  of 
five  pounds  copper  sulphate,  five  pounds  fresh  lime,  and  fifty  gallons  of 
water  may  be  used. 

Mildew.  When  this  fungus  attacks  potatoes  it  does  more  harm  than 
any  of  the  other  forms.  To  it  is  attributed  the  destructive  disease  that 
spread  over  Europe  during  the  years  1845  *o  ^So,  causing  failure  of 
the  potato  crops.  In  this  country  of  late  years,  it  seems  to  be  restricted 
to  certain  localities,  and  much  of  the  harm  supposed  to  have  been  done 
by  it  has  been  shown  by  Galloway  to  be  the  work  of  leaf  blight.  The 
two  forms  are,  however,  quite  readily  distinguished.  The  mildew 
appears  later  in  the  season,  and  is  most  vigorous  in  damp  weather.  It 
is  also  distinguished  from  the  former  disease  by  the  spots,  which  rap- 
idly enlarge  and  become  black,  while  on  the  under  side  of  these  diseased 
areas  of  the  leaves  are  to  be  found  numerous  white  threads.  These  are 
the  spore-bearing  organs.  The  fungus  also  attacks  the  tubers,  thus 
being  doubly  injurious.  The  presence  of  the  fungus  is  said  frequently 
to  be  shown  by  the  offensive  odor  that  results  from  its  injurious  action 
on  the  plants.  Apparently  this  disease  has  not  been  very  injurious  in 
this  state,  there  being  specimens  in  the  herbarium  from  Freeport  and 
Camp  Point  only,  collected  during  1882.  It  has  not  been  reported  of 
recent  years. 

To  prevent  this  disease,  the  following  precautions  are  necessary : 
Unaffected  seed  should  be  planted  on  land  free  from  spores  of  the  fungus. 
Before  the  time  of  the  appearance  of  the  disease  the  potatoes  should  be 
sprayed  with  Bordeaux  mixture,  and  the  operation  repeated  until 
danger  from  the  disease  is  past.  According  to  Mr.  L.  R.  Jones,  the 
results  that  have  followed  spraying  against  this  disease  in  Vermont, 
where  at  present  it  is  quite  injurious,  have  been  very  encouraging. 

Interior  Spotting.  What  seems  to  be  a  bacterial  or  perhaps  a 
fungous  disease  of  tubers  not  before  noticed  in  the  state  was  found  first 
during  1893  in  potatoes  raised  by  Mr.  L.  G.  Hubbard,  a  gardener  near 
Urbana,  and  later  somewhat  in  those  raised  at  this  Experiment  Station. 
The  same  thing  was  reported  from  one  or  two  other  places  in  the  state 
as  something  new.  While  this  disease  very  probably  originated  in  the 
field,  it  was  not  noticed  until  after  the  potatoes  were  dug  in  the  fall 


1895.]  FUNGOUS    DISEASES    OF    THE    POTATO.  139 

for  storage.  Mr.  Hubbard  had  four  hundred  bushels  that  in  some  cases 
were  quite  badly  affected.  The  trouble  had  never  been  noticed  in  his 
potatoes  before,  nor  did  it  make  its  appearance  the  next  season  to  any 
great  extent.  Affected  tubers  do  not  generally  show  any  sign  of  the 
disease  upon  the  outside,  but  when  cut  open  disclose  brown  spots  of 
varying  size  scattered  through  the  interior.  Very  often  these  discolored 
spots  showed  no  connection  with  the  exterior  of  the  potato,  being  sur- 
rounded by  normal  tissue.  Attempted  cultures  in  various  media  from 
affected  areas  were  unsatisfactory,  in  many  cases  giving  no  growths  of 
either  fungi  or  bacteria.  Cultures  made  during  1894-5,  however, 
seemed  to  give  results  indicating  bacterial  origin  of  the  trouble.  Sec- 
tions of  the  affected  tissue  under  the  microscope  showed  the  cell  con- 
tents in  a  disorganized  condition,  and  the  absence  of  starch  grains  that 
were  so  abundant  in  tlpe  healthy  tissue.  Nothing  like  definite  hyphal 
threads  of  a  fungus  could  be  seen,  though  sometimes  amorphous 
fungous-like  pieces  of  diseased  parts  were  found.  Occurring  so  scat- 
tered through  the  interior  of  affected  tubers  the  disease  is  naturally  one 
causing  great  waste,  as  it  is  necessary  to  cut  out  these  bad  spots  in  pre- 
paring potatoes  for  table  use.  Last  year  the  disease  was  heard  of 
definitely  but  once.  The  Station  would  at  any  time  be  glad  to  receive 
information,  or  material  for  investigation,  from  any  source. 

Bundlt  Blackening.  This  is  a  fungous  trouble  of  stored  potatoes 
which  shows  as  small  dots  or  lines  a  short  distance  from  the  surface. 
The  disease  is  one  of  the  bundles,  which  form  a  band  running  around 
the  potato  a  short  distance  inside.  These  bundles  originate  at  the  stem 
end  and  send  off  a  few  bundles  to  each  of  the  eyes.  The  fungus  gains 
entrance  probably  after  the  potatoes  are  gathered  through  the  dead 
stem,  and  proceeds  from  this  through  the  bundles,  causing  them  to  turn 
black  as  the  result  of  its  attack.  While  not  a  very  serious  malady,  it  is 
objectionable,  as  it  opens  the  way. for  other  fungi  and  bacteria  so  that 
often  tissue  in  the  neighborhood  of  the  affected  bundles  becomes  dis- 
eased and  a  general  rotting  is  started.  It  may  also  cause  a  slight  waste 
and  some  trouble  in  cleaning  potatoes  for  use.  The  fungus  is  quite 
similar  to  the  one  causing  the  following  trouble. 

Dry  End-Rot.  This  name  is  given  because  the  dry  decay  that 
takes  place  in  this  disease  of  stored  potatoes  begins  at  one  end.  It 
affects  all  the  tissue  as  it  slowly  advances  forward,  until,  perhaps,  the 
whole  tuber  is  destroyed.  As  in  the  preceding  case,  the  trouble  begins 
at  the  stem  end,  the  fungus  gaining  entrance  after  the  rupture  of  the 
tuber  from  the  plant.  It  seems  to  be  one  of  the  most  common  and 
worst  troubles  of  our  stored  potatoes.  The  trouble  is  caused,  at  least  in 
great  part,  by  a  mold-like  fungus  that  shows  itself  on  the  exterior,  when 
the  potato  is  in  a  moist  place,  by  little  tufts  of  white  spore-bearing 
threads.  Though  commonly  known  to  scientists  as  Fusarium  Solani, 
Reinke  and  Berthold  class  this  fungus  as  one  of  the  conidal  stages  of 
Hypomyces  Solani.  The  decay  is  accompanied  more  or  less  by  other 


140  BULLETIN    NO.    40.  \April 

forms  of  fungi  and  by  bacteria,  which  materially  aid  in  further  decom- 
position of  the  affected  cells  and  their  contents.  Perhaps  the  best  way 
to  prevent  this  and  other  decay  of  stored  potatoes  is  to  see  that  no 
unsound  tubers  are  put  away  when  the  tubers  are  stored,  and  to  keep 
them  in  a  dry  cool  place. 

Besides  the  foregoing  troubles,  potatoes  here  have  been  subject  to 
wet  rot,  said  to  be  of  bacterial  origin.  Also  associated  with  the  various 
forms  of  decay  in  stored  potatoes,  and  perhaps  more  or  less  injurious  in 
such  case,  have  been  found  several  species  of  bacteria;  a  blue  mold, 
Penicillium  crustaceum\  a  red  mold,  Verticillium  cinnabar  mum  of 
Reinke  and  Berthold ;  also  Stysanus  stemonitis,  Tricothecium  roseum,  and 
a  species  of  a  white  Verticillium. 

G.  P.  CLINTON,  M.  S., 

Assistant  Botanist. 

ILLUSTRATIONS. 

Fig.  i.  Showing  appearance  of  potato  leaf  when  affected  by  mildew.  [Copied 
from  illustration  issued  by  Div.  of  Veg.  Path.,  U.  S.  Dept.  Agr.] 

Fig.  2.  Showing  appearance  of  potato  leaf  when  affected  by  leaf  blight. 
[Copied  as  above.] 

Fig.  3.  Showing  potato  tubers  affected  by  scab  in  different  degrees,  A  being  free 
from  scab. 

Fig,  4.     Showing  potato  tubers  affected  by  dry  end-rot  in  different  degrees. 


AN  EXPERIMENT  TO  PREVENT  SCAB  AND  LEAF 
BLIGHT  OF  POTATOES. 

A  combined  experiment  to  determine  the  value  of  treating  the 
seed  with  corrosive  sublimate  for  prevention  of  scab,  and  of  spraying 
the  vines  with  Bordeaux  mixture  for  prevention  of  leaf  blight  was  un- 
dertaken in  a  very  exact  manner,  though  on  a  small  scale.  Three 
varieties  of  potatoes  were  selected — one  early,  Howe's  premium,  and 
two  late,  Quinnipiac  and  Alexander's  prolific.  Of  these  the  seed  of  the 
first  two  was  only  slightly  scabby,  while  that  of  the  last  was  rather 
badly  scabbed.  Those  receiving  seed  treatment  were  soaked  for  one 
and  a  half  hours  in  a  solution  of  corrosive  sublimate  of  the  strength 
recommended  by  Bolley  *  (2^  oz.  in  15  gal.  of  water).  After  drying, 
the  treated  and  untreated  seed  was  cut  in  pieces  of  as  uniform  size  as 
possible,  leaving  one  eye  to  each  piece.  The  potatoes  were  planted 
April  26th  in  five  different  plats.  Twenty  pieces  were  placed  in  each 
row  at  a  distance  of  fourteen  inches  apart,  with  the  rows  three  and  the 
plats  seven  feet  apart.  In  each  plat  were  planted  two  rows  of  each  of 
the  three  varieties,  and  all  in  the  plat  received  the  same  treatment.  The 

*Bull.  No.  9,  Esp.  Sta.,  North  Dak. 


1895.] 


FUNGOUS    DISEASES    OF    THE    POTATO. 


142  BULLETIN    NO.     40.  \_April, 

method  of  treatment  for  each  plat  is  given  in  the  table  which  follows- 
The  land  had  never  been  used  for  a  root  crop  before,  and  had  most  of 
the  drainage  away  from  it.  Such  care  was  taken  so  that  the  conditions 
might  be  exactly  the  same,  save  the  treatment  given,  in  order  that  a 
trustworthy  basis  might  be  had  for  determining  the  value  of  each  treat- 
ment. The  potatoes  were  planted  so  late  that  the  early  variety 
amounted  to  little,  dying  by  the  first  of  August;  but  the  late  varieties, 
having  the  benefit  of  August  rains,  did  better  than  early  planted 
potatoes,  for  which  the  rains  came  too  late.  The  late  varieties  lived 
until  killed  by  frost  the  first  part  of  October.  The  vines  mostly 
appeared  between  May  yth  and  22d.  The  sprayed  vines  were  so 
treated  six  times,  as  follows:  June  nth,  June  23d,  July  6th,  July  23d, 
Aug.  3d,  and  Sept.  loth.  The  spraying  was  given  very  thoroughly 
and  quite  abundantly.  The  Bordeaux  mixture  used  consisted  of  5  Ib. 
copper  sulphate,  5  Ib.  fresh  lime,  50  gal.  water.  In  the  case  where 
Paris  green  was  used  one-half  pound  was  added  to  the  above  formula. 
The  first  spraying  was  given  while  the  plants  were  comparatively 
young,  as  on  June  nth  these  potatoes  were  about  two  weeks  later  in 
development  than  most  potatoes.  By  July  3d  but  little  of  the  blight 
had  yet  appeared  on  the  later  varieties,  though  most  potatoes  at  this 
time  were  quite  badly  affected  July  lyth  showed  the  potatoes  begin- 
ning to  blight  somewhat,  but  showing  no  difference  to  the  eye,  as  re- 
gards blighted  leaves,  between  those  sprayed  and  those  not  sprayed. 
The  potato  bugs  were  beginning  to  damage  the  vines,  and  in  this 
respect  there  was  a  difference  between  sprayed  and  unsprayed  vines. 
The  bugs  did  not  seem  to  affect  the  vines  sprayed  with  Bordeaux  mix- 
ture alone  very  much  more  than  those  sprayed  with  both  Paris  green 
and  Bordeaux  mixture.  The  unsprayed  vines,  however,  suffered  con- 
siderably. The  August  rains  helped  all  the  vines  of  the  late  varieties 
wonderfully,  so  that  in  September  they  were  as  green  looking  as  they 
were  the  first  of  August.  While  the  blight  on  the  late  varieties  was 
not  so  severe  in  any  case  as  on  other  potatoes  in  this  vicinity,  so  far  as 
one  could  judge  from  affected  leaves,  there  was  no  difference  at  any 
time  between  the  plats  sprayed  and  those  not  sprayed. 

Scab.  To  determine  the  benefit  of  treatment  accurately,  one  must 
compare  a  treated  variety  with  a  corresponding  untreated  one.  Dealing 
first  with  the  results  of  treatment  for  scab,  we  can  compare  the  number 
of  scabby  potatoes  from  the  treated  plats  A,  B,  C,  with  those  from  the 
untreated  D,  E?  as  spraying  would  in  no  way  affect  the  number  of 
scabby  potatoes,  though  it  might  the  yield  from  these  plats.  We  have, 
then,  from  the  treated  variety  of  Alexander's  prolific  11,  9,  and  13  per 
cent,  of  scabby  potatoes  to  compare  with  38  and  43  per  cent,  from  those 
untreated,  showing  extreme  gains  of  25  and  34  per  cent,  of  sound 
potatoes  for  the  treatment.  The  reason  why  the  treated  seed  in  this 
case  gave  so  high  a  percentage  of  scabby  potatoes  probably  lies  in  the 
fact  that  the  treatment  was  not  continued  long  enough,  as  the  seed 


1895.] 


SCAB    AND    LEAF    BLIGHT    OF    POTATO. 


H3 


H 

a   « 


a 

(i.     U 

o    z 

Q    2 
z    S 

<   o 


<  D 

S  H 

J  £ 

03  g 

P  * 

C/5  X 
D 

35  a 


^ 

rj 

m 

m 
in       t^ 

m 
t^ 

m    • 
in  t>.    • 

m 
in  t^ 

>l 

S 

M      N 

M               M              O 

m 

w        ro      oo 
m 
4— 

MM        • 

IN     M     O 
•*• 

"rt 
C/) 

0    t^ 
oo  m 

m       m       ft 
t^       t^       m 

w         O         f«l 
OO           M           -T 

O  m    • 

CTivO      • 

N  00    PO 

vo  oo  vo 

lumber. 

Medium. 

r^  m 

N  m 

co       r^       t^ 
•>f       m       N 

S1     *     m 

PO       m       fo 

PJ    O      • 
TI-  m    • 

o  a\  o 

•^-  N 

T3 

a 
a 

<o 

45 

00 

c 

,3 

M    VO 
N     M 

t^       m      oo 

M           M 

m       m       m 

N           •*• 

ro  O     • 

N    PO     • 

M    00     O 
M 

(75 

Very  large. 

m  M 

O         Ci        O 

^-       m       o 

VO   m    • 

O    M    0 

a 
t 

P 

i  >> 

J  XI 
•>Xi 
,  rt 

J 

+  1  1 

M   mvo 

M 

+        1 
CTi         -f        t^ 

m       PO        •^« 

00    PO  P) 

++ 

PO  PO  PO 

•*•    M      PO 

T3 

6 

V 
14 

(14 

oo  N  in 

M      O    00 
M      M 

OO         Ov         O 
m       m       M 

M                M                M 

Tt-        00           •<!- 
PO           M             M 

M              PI              M 

M   o  in 
O    0    I-x 

i»-  Ov  ro 
VO    O  00 

0 
T) 

U 
hi 

lumber. 

>, 

XI 

X) 
rt 
u 
C/5 

m  m  in 

m       f-      oo 

M 

O       vo        m 

N 

O  O  m 
vo  m  PO 

C*  t^  O 

•*•    M      TJ- 

£ 

(A 

4) 

a 

•«4 

5 

m  t-»  O 

m  o   (7> 

M             VO             OO 

in       O         M 

•*•         •*•         CTi 

m       P»        w 

MOO 

vo  m  M 

POVO    PO 

M      P<      PI 

a 

3 

H 

DC 

3 

OJ 
V 

u 

u< 

m    • 
>n  c^    • 

O>  O      • 
1-1    N       • 

>n       m 
PI        N 

M              CO             O 

N        m       M 

in 
m       PI 

o       -i-       * 

PO           •^• 

m  m    • 
t^oo     • 

MM          * 

m    . 

M      • 

M  m    • 

MM         • 

T3 

"o 

a 

Xj 

J5 

_ec 
'£ 

>, 

XI 
X) 
rt 
o- 
C/D 

in    . 
in  r^    • 

N 

m       m 
f^       t^- 

PO                               M 

m       in 

M          t>- 

•<!- 

m    • 
m  t^    • 

PO  o    • 

MM        « 

m 

vo   PO    . 

« 

Xj 

o 
•Q 

£ 

"c3 

r^ 

moo 

m                  m 

N                         N 

in                 m 

t-^                       N 

m  PI 

Cl     M 

in  PO 

m  p»  CTV 

2 

•a 

o 
H 

p«  M  in 

N    N 

*       S?       H 

<N           fO          M 

•*•       m       « 

m             Tf             M 

M     O~IVO 
PO  (N 

t^oo   •*• 

M     M 

"rt 

i           : 

" 

1 
'i 
c 
> 

•^ 
1 

i 

Alexander's  prolific. 
Quinnipiac  
*Howe's  premium.. 

Alexander's  prolific. 
Quinnipiac  
Howe's  premium.  .  . 

Alexander's  prolific. 
Quinnipiac  
Howe's  premium... 

Alexander's  prolific. 
Quinnipiac  
*Howe's  premium.  . 

Alexander's  prolific. 
Quinnipiac  
Howe's  premium.  .  .  . 

0) 

B 
<L> 
<U 

in 
u 

_a 
"> 
a 
^ 

a 

u 

Treated  seed 
with  corrosive 
sublimate. 

Treated  seed 
with  cor.  sub. 
Sprayed  with 
Bordeaux 
mixture. 

Treated  seed 
with  cor.  sub. 
Sprayed  with 
Bordeaux  mix. 
combined  with 
Paris  green. 

Sprayed  with 
Bordeaux 
mixture. 

No  treatment. 

J3 
Z 

T3 
PO 

60    .! 

3     S 

<    XI 
60    E 
3     3 

Q  fc 

p 

3 

i 

<! 

PQ 

U 

Q 

W 

144  BULLETIN    NO.    40.  [April, 

of  this  viriety  was  much  more  scabby  than  that  of  the  others.  From 
the  treated  Quinnipiac  we  have  5,  4,  and  3  per  cent,  scabby  potatoes  in 
the  three  plats,  while  the  two  untreated  gave  33  and  13  per  cent.,  show- 
ing extreme  gains  of  8  and  30  per  cent,  for  the  treatment.  Howe's 
premium  gave  in  treated  plats  6,  7,  and  4  per  cent,  scabby  tubers  to  be 
compared  with  32  and  33  per  cent,  from  the  untreated  plats,  or  extreme 
gains  of  25  and  29  per  cent,  for  treatment.  Thus  the  experiment  shows 
a  varying  gain  in  sound  potatoes  of  8  to  34  per  cent,  due  to  seed  treat- 
ment. This  gain  would  probably  have  been  much  greater  had  a  longer 
treatment  (three  hours)  been  given  and  had  the  seed  used  happened  to 
have  been  very  scabby. 

These  percentages  so  far  show  only  gain  in  quality  resulting  from 
treatment.  The  experiment,  however,  in  every  case  save  one,  shows  a 
gain  in  quantity.  To  determine  this  we  can  only  compare  plats  A  with 
E,  and  B  with  D.  In  the  first  comparison,  Alexander's  prolific  has  a 
total  weight  of  22  Ib.  in  the  treated  to  17^  Ib.  in  the  untreated,  a  gain 
of  4}^  Ib.  With  the  Quinnipiac  the  treated  yields  21^2  Ib.  to  18^ 
Ib.  from  the  untreated,  a  gain  of  31^  Ib.  Howe's  premium  in  the 
treated  plat  gives  57/6  Ib.  to  4  15-16  Ib.  in  the  untreated,  the  gain  being 
15-16  of  a  pound.  In  the  second  case  Alexander's  prolific  shows  a  loss 
of  64^  Ib. ;  Quinnipiac,  a  gain  of  4^  Ib. ;  and  Howe's  premium,  a  gain 
of  51^5  Ib.  In  the  case  of  Howe's  premium  the  gain  would  not  nor- 
mally have  been  so  large,  as  those  in  plat  D  were  dug  before  the  vines 
were  entirely  dead.  In  all  a  gain  for  treatment  of  n  13-16  Ib.  was 
had,  or  10  per  cent  of  the  lots  treated. 

Besides  the  gain  in  tubers  of  better  appearance  and  the  slight  gain 
in  weight,  there  is  also  another  source  of  gain  in  the  treatment.  In 
preparing  potatoes  for  table  use  there  is  a  greater  waste  in  scabby  than 
in  sound  ones.  The  loss  from  this  source  in  the  experimental  potatoes 
was  obtained  as  follows:  Ten  pounds  each  of  the  scabby  and  sound 
tubers  were  used  for  household  purposes,  the  peeling  in  each  case  being 
saved.  In  the  scabby  lot  the  waste  was  two  pounds,  three  ounces, 
while  in  the  sound  lot  the  waste  only  amounted  to  one  pound,  three 
ounces,  showing  a  waste  of  an  extra  pound  or  ten  per  cent,  due  to  scab. 
Of  course  this  waste  will  vary  according  to  the  extent  of  the  scab. 
From  the  three  sources  of  profit  thus  gained  by  seed  treatment  when 
the  potatoes  are  planted  on  uninfected  land,  one  can  readily  see  that  the 
gain  much  overbalances  the  small  cost.  The  cost  of  treatment,  includ- 
ing labor,  need  not  exceed  seventy-five  cents  to  one  dollar  per  acre. 

Leaf  Slight.  The  spraying  part  of  the  experiment  also  shows 
good  results,  as  seems  to  be  the  case  with  most  experiments  that  have 
been  made  along  this  line.  Care  in  this  part  of  the  experiment  was 
taken  to  notice  the  total  weight  of  potatoes  produced  and  the  number 
of  different  sized  ones.  The  comparisons  in  this  case  may  be  made 
between  plats  A  and  B,  and  D  and  E.  In  the  first  we  find  sprayed 
Alexander's  prolific  yielding  24^  Ib.,  unsprayed  ones  22  Ib. ,  a  gain  of 


1895-]  SCAB    AND    LEAF    BLIGHT    OF    POTATO.  145 

2^  lb. ;  of  the  Quinnipiac  sprayed  ones  gave  34  lb.,  and  unsprayed 
ones  -21^/2  lb.,  a  gain  of  12^  lb. ;  and  Howe's  premium  when  sprayed 
gave  1 1  y±  lb. ,  and  unsprayed  gave  5/^  lb.,  a  gain  of  5^  lb.  Compar- 
ing plats  D  with  E,  sprayed  Alexander's  prolific  showed  a  gain  of  13^ 
lb.  over  unsprayed  ones;  the  Quinnipiac  variety  gave  a  gain  of  ti  lb. ; 
and  Howe's  premium  had  i  3-16  lb.  gain.  We  have  a  total  gain  of 
nearly  46  pounds  for  the  treatment.  This  means  that  one-third  of  the 
potatoes  of  the  sprayed  plats  was  due  to  the  treatment.  The  benefit  of 
spraying,  however,  did  not  limit  itself  to  the  production  of  a  greater 
weight  of  potatoes,  but  a  glance  at  the  columns  giving  number  of  dif- 
ferent sized  potatoes  shows  that  the  number  of  very  large,  large,  and 
medium  potatoes  was  always  greater  in  the  sprayed  than  in  the  cor- 
responding unsprayed  varieties. 

The  claim  is  not  made  that  all  or  any  considerable  part  of  this 
increased  yield  is  due  to  the  prevention  of  leaf  blight;  in  fact  it  is 
believed  that  at  least  a  large  part  of  it  is  due  to  the  partial  exemption 
of  sprayed  plats  from  attack  by  the  potato  bug.  As  was  said  before 
there  seemed  to  be  no  difference  in  the  plats  whether  sprayed  or  not  as 
to  the  number  of  leaves  showing  blight.  Plat  C,  which  was  sprayed 
with  Paris  green  as  well  as  Bordeaux  "mixture,  gave  with  each  variety 
the  greatest  yield,  thus  seeming  to  indicate  that  while  Bordeaux  mixture 
alone  kept  off  the  bugs  fairly  well  it  was  not  a  complete  preventive. 
There  being  no  plat  that  was  kept  free  from  the  potato  bug  to  com- 
pare with  one  also  kept  free  and  sprayed  with  Bordeaux  mixture,  we 
draw  no  definite  conclusions  as  to  the  value  of  this  fungicide  as  a  pre- 
ventive for  leaf  blight. 

RESULTS  IN  SUMMARY. 

1.  Corrosive  sublimate  treatment  of  seed,  as  a  preventive  for  scab,  with  potatoes 
planted  on  uninfected  land;   gave  not  only  from  8  to  34  per  cent,  more  of  sound 
potatoes,  but  also  increased  the  yield  10  per  cent,  and  rendered  less  the  waste  in 
preparation  for  household  use. 

2.  Early  and  frequent  spraying  with  Bordeaux  mixture  gave  an  increase  of  one- 
third  the  total  yield. 

3.  Paris  green  added  to  Bordeaux  mixture  gave  an  additional  increase  equal  to 
one-third  those  sprayed  with  Bordeaux  mixture  only. 

4.  In   the  case  of  spraying  the  benefit  was  due  to  limiting  the  attack  of  the 
potato  bug,  and  possibly  to  preventing  somewhat  leaf  blight. 

G.   P.   CLINTON,  M.  S., 

Assistant  Botanist. 


146  BULLETIN    NO.    40.  \Aprtl,    1895. 


ORGANIZATION. 


BOARD  OF  TRUSTEES  OF  THE  UNIVERSITY  OF  ILLINOIS. 

NELSON  W.  GRAHAM,  Carbondale,  President. 
JOHN  P.  ALTGELD,  Springfield,  Governor  of  Illinois. 
JAMES  W.  JUDY,   Springfield,  President  State  Board  of  Agriculture. 
SAMUEL  M.  INGLIS,  Springfield,  Superintendent  Public  Instruction. 
RICHARD  P.  MORGAN,  Dwight.  ISAAC  S.  RAYMOND,  Sidney. 

DR.  JULIA  H.  SMITH,  Chicago.  SAMUEL  A.  BULLARD,   Springfield, 

NAPOLEON  B.  MORRISON,  Odin.  ALEXANDER  McLEAN,  Macomb. 

JAMES  E.  ARMSTRONG,  Chicago.  MRS.  LUCY  L.  FLOWER,  Chicago. 

ANDREW  S.  DRAPER,  LL.D.,  President  of  the  University. 

BOARD  OF  DIRECTION  OF  THE  EXPERIMENT  STATION. 

THOMAS  J.  BURRILL,   PH.D.,  Urbana,  Prof,  of  Botany  and  Horticulture,  Pres 
E.  E.  CHESTER,  Champaign,  of  State  Board  of  Agriculture. 

E.  A.  RIEHL,  Alton,  of  State  Horticultural  Society. 
H.  B.  CURLER,  DeKalb,  of  State  Dairymen's  Association. 

N.  B.  MORRISON,  Odin,  Trustee  of  the  University. 

ISAAC  S.  RAYMOND,  Sidney,  Trustee  of  the  University. 

STEPHEN  A.  FORBES,  PH.D.,  Urbana,  Professor  of  Zoology. 

EUGENE  DAVENPORT,  M.  S.,  Urbana,  Professor  of  Animal  Husbandry. 

THE  STATION  STAFF. 

THOMAS  J.  BURRILL,  PH.D.,  Horticulturist  and   Botanist,   President  Board    of 

Direction. 

WILLIAM  L.  PILLSBURY,  A.M.,  Urbana,  Secretary. 
EUGENE  DAVENPORT,  M.  S.,  Urbana,  Agriculturist. 

CYRIL  GEORGE  HOPKINS,   M.S.,  Chemist. 
STEPHEN  A.  FORBES,  PH.D.,  Consulting  Entomologist. 

DONALD  McINTOSH,  V.S.,  Consulting  Veterinarian. 
GEORGE  W.  McCLUER,  M.S.,  Assistant  Horticulturist. 

GEORGE  P.  CLINTON,  M.S.,  Assistant  Botanist. 

FRANK  D.  GARDNER,  B.S.,  Assistant  Agriculturist. 

WILL  A.  POWERS,  B.S.,  Assistant  Chemist. 


• 


<Cv~  "tsSSS 


UNIVERSITY  OF  ILLINOIS-URBAN* 


